With regard to the rear-wheel steering apparatuses, there has been suggested a rear-wheel steering apparatus for preventing transmission of a driving force from a rear-wheel side (e.g. refer to a patent document 1). According to the vehicular rear-wheel steering apparatus disclosed in the patent document 1, it is possible to certainly prevent the steering angle of rear wheels from being changed by placing a worm gear and an irreversible clutch mechanism, which allows the transmission of a driving force to the rear-wheel side from an actuator side to prevent the transmission of the driving force in the opposite direction, in a power transmission channel for transmitting the driving force to the rear wheels from the actuator.
Incidentally, in technical fields that differ from the rear-wheel steering apparatuses, there has been also suggested an electric power steering apparatus for reducing a drive current for a motor, near a rudder angle end (e.g. refer to a patent document 2).    Patent document 1: Japanese Patent Application Laid Open No. 2003-237614    Patent document 2: Japanese Patent Application Laid Open No. 2007-269070